The present invention relates to an electrically operated lock, particularly for motor vehicle doors. It should be pointed out that, in the following description and claims, the term "door" is used in the general sense to indicate both the front and rear side doors and the rear door of the vehicle.
More and more vehicles are being fitted with electrically operated locks which, with very little effort on the part of the user, provide for high locking loads and, consequently, high compression loads on the door seals, thus improving passenger comfort by reducing noise and air intrusion.
Known locks of the aforementioned type usually comprise a latch mounted for rotation on a pin integral with the vehicle door, and designed to move between an unlatched position and a fully latched position wherein it engages a striker secured to the vehicle frame; a retainer loaded by elastic means and designed to cooperate with and maintain said latch in the latched position; linkages for enabling mechanical release and the safety function; and electric activating means.
Said electric activating means usually provide for automatically closing the latch when the door is pushed to and the latch set to what is generally referred to as the "secondary latched" position, wherein the retainer engages the latch in less than the fully closed position. Commencing from said secondary latched position, the latch is turned further into a position in excess of the fully latched position, so as to enable engagement of the retainer via said elastic means.
Known locks of the aforementioned type present a number of drawbacks.
First and foremost is the risk element involved in said electric activating means operating in said secondary latched position, wherein the door is still slightly ajar and fingers or objects may inadvertently be trapped between the door and vehicle body when said electric activating means are operated.
Secondly, due to the fairly steep load-distortion curve of the door seals when subjected to maximum compression, rotation of the latch in excess of the fully latched position places considerable extra load on the electric activating means, which must thus be oversized.
Thirdly, known locks of the aforementioned type are fairly noisy, due to the latch being sprung back sharply by said elastic means from the overtravel to the fully latched position.